Michael Dahl 
Thirteenth Mystery [PDF ebook] 

Abracadabra, the founder of the Hocus Pocus Hotel has vanished! Charlie Hitchcock and Tyler Yu team up again to solve this mystery and find their friend. As the boys continue to search for clues, and as Annie Solo, a desk clerk at the hotel, helps them out, the last thing they expect happens. Tyler vanishes. But Charlie has reason to believe that a mysterious thirteenth floor exists in the old hotel . . . Charlie finds himself on the hidden 13th floor of the Abracadabra Hotel. He discovers both Tyler and the magician Brack. But how did the two get trapped there in the first place, and will they be able to work out who is plotting against the Hocus Pocus Hotel before it’s too late?